Two new Ni and Zn metal-organic frameworks of glutarate and 1,4-bis[(2-methyl-1H-imidazol-1-yl)methyl]benzene ligands: syntheses, structures and luminescence sensing properties.

Two new metal-organic frameworks (MOFs), namely, three-dimensional poly[diaquabis{μ-1,4-bis[(2-methyl-1H-imidazol-1-yl)methyl]benzene}bis(μ-glutarato)dinickel(II)] monohydrate], {[Ni(CHO)(CHN)(HO)]·HO} or {[Ni(Glu)(1,4-mbix)(HO)]·HO}, (I), and two-dimensional poly[[{μ-1,4-bis[(2-methyl-1H-imidazol-1-yl)methyl]benzene}(μ-glutarato)zinc(II)] tetrahydrate], {[Zn(CHO)(CHN)]·4HO} or {[Zn(Glu)(1,4-mbix)]·4HO} (II), have been synthesized hydrothermally using glutarate (Glu) mixed with 1,4-bis[(2-methyl-1H-imidazol-1-yl)methyl]benzene (1,4-mbix), and characterized by single-crystal X-ray diffraction, IR and UV-Vis spectroscopy, powder X-ray diffraction, and thermogravimetric and photoluminescence analyses. Ni MOF (I) shows a 4-connected 3D framework with point symbol 6, but is not a typical dia network. Zn MOF (II) displays a two-dimensional 4-sql network with one-dimensional water chains penetrating the grids along the c direction. The solid-state photoluminescence analysis of (II) was performed at room temperature and the MOF exhibits highly selective sensing toward Fe and CrO ions in aqueous solution.